Does building height influence bird diversity in urban landscapes?

Abstract

Context: Urbanization impacts biodiversity through changes in horizontal and vertical structures. While impervious cover is well-studied, the role of building height remains underexplored at a broad scale. Objectives: This study aimed (1) to assess whether building height differed statistically from impervious cover and NDVI in explaining bird diversity in cities, and (2) to assess the impacts of building height in conjunction with seven predictor variables: impervious cover, bare, trees, grass, water, shrub and scrub and NDVI. Methods: We combined land cover data with an open-access building footprints data. We analyzed over 1 million eBird checklists from 298 cities in the United States. For objective one seven models were evaluated for each city (1) building height, (2) impervious cover, (3) NDVI, (4) building height and impervious cover, (5) building height and NDVI, (6) impervious Cover and NDVI, and (7) building height, impervious Cover and NDVI. For objective two we use model 7 and the rest of the predictor variables to assess the impact of building height. For both objectives, we compared model results by ecoregion. Results: Building height, impervious cover, and NDVI were the best single predictors of bird species richness in 10.7%, 10.4%, and 12.4% of cities, respectively. However, the combined model including all three variables performed best in 25.8% of cities, underscoring the complementary influence of vertical and horizontal urban structures in cities. Species richness was positively related to shrub/scrub and water cover, highlighting the importance of these habitats for urban biodiversity. Conclusions: Our research advances landscape ecology by incorporating vertical urban structure into biodiversity models, providing new insights into the multidimensional impacts of urbanization on bird communities. Findings underscore the need for context-specific strategies integrating green infrastructure to promote avian diversity in cities.